The objective of this study is to evaluate the impact of home-based primary care (HBPC) on outcomes for homebound older adults, including hospitalization and emergency department (ED) visits, quality of life and symptom control, costs of care, and burden of care for their informal caregivers. We will also conduct a mixed methods dissemination and implementation evaluation of HBPC. Over one million seniors in the U.S. have functional limitations that prevent them from receiving office-based primary care (OBPC). As a result, homebound adults typically experience poor disease control, high rates of hospitalization, and large healthcare expenditures resulting for hospitalizations and ED use. Few modes of healthcare delivery designed specifically for the homebound have been studied, but observational data suggest that HBPC could improve outcomes and reduce spending for these highly vulnerable patients. We propose a pragmatic randomized controlled trial of HBPC vs. OBPC for homebound older adults, with 3 Specific Aims: to compare the impact of HBPC and OBPC 1) on hospitalization and ED visit rates, symptom control and quality of life, and satisfaction with care among homebound elders; 2) on caregiving burden among informal caregivers (e.g., family and friends); and 3) on healthcare expenditures for the homebound. We hypothesize that patients in HBPC and their caregivers will have better outcomes compared to OBPC patients. We will recruit 350 homebound adults ? 65 years in New York City from outpatient clinical and community- based settings. HBPC will be delivered through Mount Sinai Visiting Doctors or the Chelsea Village House Calls Program. Patients randomized to OBPC will continue to receive care from their usual outpatient primary care provider or will be assigned one within the Mount Sinai healthcare system. We will conduct interviews in English and Spanish at baseline and quarterly thereafter up to 1 year. Medicare and Medicaid claims data will be used to determine healthcare utilization and costs. The study embraces the concepts of a pragmatic trial design to facilitate the translation of study findings for practical clinical, systms, and health policy applications. The study team includes experts in aging related health services research, health economics, health policy, randomized clinical trials, and the medical and nursing care of homebound older adults. The proposed study would be the largest prospective study of homebound older adults and the only randomized trial of HBPC for the homebound. It would fill important knowledge gaps in our understanding of the effects of HBPC for the homebound. The study is consistent with the Institute of Medicine's call for expanded research on comprehensive models of chronic care, including the multidisciplinary management of chronic diseases and the medical home concept.